During rock drilling of long drill holes, it is necessary to join a plurality of drill strings component for forming a drill string. During core drilling aiming to extract a drill core, it is often drilled to very great depths and distances. As an example it is common with drill holes measuring thousands of meters. The aim of core drilling is to investigate the rock ground at a distance in order, among other things, to determine the conditions for extracting minerals.
Core drilling is preformed with the aid of a rotating drill bit being driven by a rock drilling machine in the form of a rotational unit being arranged of a drill rig. During the rotational operation of the rotation unit, the rock drilling machine is simultaneously fed forwardly in the drilling direction through a feed mechanism being arranged on a linear guide, such as a feed beam.
In practice, a great part of the handling of the drill string components, which in the case of core drilling are tubular elements, is made manually, which results in a number of problems. Because of the often substantial weight of the components and that the handling position on the drill rig is difficult to access, the manual handling puts strain of the operator, also if it is preformed appropriately. It should be added that there is a risk of the operator being injured in connection with the handling. Further, the manual handling may lead to damaged drill string components and in particular their threaded portions because of intentional or unintentional careless handling of the elements.
Because of a manual handling being relatively slow and that the time when the drill rig stands still is relatively long, seen over a drilling sequence, the effectiveness of the rig is affected in a negative direction.
From U.S. Pat. No. 6,634,443 is previously known a device for handling drill string components, which, however, is complicated and requires positioning, which increases the problems with accessibility in connection with the basically manual handling of extracted drill cores.